1. Field of Invention
This invention relates generally to the cooling of lubricating fluids of engines and particularly to an adapter unit incorporating a relief valve for attaching an auxiliary cooling element in a closed lubricating system. In particular, the invention relates to a thermostatic relief valve in an adapter which couples a spin-on type oil filter to an automotive engine in a manner which does not require altering the filter unit.
Automotive engines, particularly engines subject to heavy loading such as recreational vehicles and racing vehicles frequently can benefit from an auxiliary device for cooling the lubricating oil in a closed lubricating system. Otherwise, the lubricating oil can overheat and its lubricating ability can be compromised, thereby resulting in increased engine wear and possible engine failure.
In order to provide a remedy to this problem, auxiliary oil cooling devices have been developed which include an oil cooling radiator coupled to an adapter which is positioned between the oil filter and the engine connection for the oil filter. Although such auxiliary oil coolers are relatively well-known, a particular problem has been the maintenance of the lubricating oil above acceptable minimum temperatures for most efficient engine operation, as well as the provision of pressure relief and fluid bypass in the event of excessive pressure differential within the adapter of the closed fluid circuit system. A valve is therefore needed which can assure a constant supply of fluid within a safe operating temperature and pressure range under the most adverse operating conditions.
2. Description of the Prior Art
Devices for cooling engine lubricating fluids are well-known. Representative disclosures are U.S. Pat. Nos. 2,068,395; 2,348,247; and 3,463,317.
Oil cooler adapters incorporating one-way pressure relief valves are known as for example a unit manufactured by Thermo-Chem Corporation of Tulsa, Oklahoma.
Bimetal strips are well-known expedients for operating thermostatic switches particularly where simple make and break electrical contact is required. Also known are electrical switches having bimetal strips with a 180.degree. reversal of surfaces. See for example U.S. Pat. Nos. 3,656,080 and 2,415,473.
A bimetal element is known for operating a poppet valve in a gas line, as for example U.S. Pat. No. 2,227,901 wherein a reversed bimetal element is used as part of a device for urging a single poppet valve to translate within a valve guide.